Computer networks connect computer systems and other network devices, collectively called “nodes” or “hosts,” in a manner that enables them to exchange data. While many networks are composed of wired connections, the term “network” also describes wireless networks of various sorts. Nodes in the same network are typically each identified using a network address that is unique within the network.
A network may host one or more logical networks, which are also referred to as “subnetworks” (or “subnets”) of the network. Subnets are defined by the subset of all possible network addresses that they contain. In a network having subnets, the network addresses of the nodes are said to contain two components, or “parts”: a “network part” identifying the particular subnetwork of which the node is a member, whose contents are invariant across the network addresses of the nodes of a particular subnetwork, and a “host part” identifying the particular node within the subnetwork.
The amount of space in the network addresses of nodes in a particular subnet needed for the host part varies with the number of nodes in the subnetwork, as more space is required to uniquely identify larger numbers of nodes. Accordingly, many addressing schemes allow the size of the host part of the network address, and, correspondingly, the size of the network part, to vary from subnet to subnet.
In many situations, it is useful to identify any subnets operating on a given network. This information is often needed when adding a new node, such as a network security device or a router, to the network, or when configuring an existing node within the network.
In general, identifying a subnet involves both (1) identifying the portion of network addresses of the subnet that is devoted to the network part, and (2) determining the content of the network part. To identify the subnets of a particular network, it is common for a network specialist to physically visit and interrogate one or more nodes of the network. This approach is both expensive and time-consuming, as it requires the physical presence of a scarce network specialist.
In view of the foregoing, a facility for automatically identifying subnets in a network would have significant utility.